Research reveals how MS harms brain before symptoms appear
Multiple sclerosis may begin damaging the brain up to seven years before symptoms appear, researchers say, showing immune activity starts earlier than previously thought.
By analysing more than 5,000 blood proteins, scientists have mapped when MS begins attacking the myelin sheath — the fatty layer protecting nerve fibres — and identified potential diagnostic markers.
Myelin enables efficient electrical signalling through the nervous system, and its loss leads to the nerve damage seen in MS.
Scientists at UC San Francisco analysed blood from 134 people with MS, using samples from the US Department of Defense Serum Repository.
The collection holds blood samples from service members taken when they apply to join the military, providing rare long-term insights.
Seven years before diagnosis, the team saw a rise in MOG (myelin oligodendrocyte glycoprotein), a sign of myelin injury. A year later, levels of neurofilament light chain — a marker of nerve fibre damage — increased.
During this period, IL-3 and related immune proteins appeared in the blood. IL-3 recruits immune cells to the brain and spinal cord, where they attack nerve cells.
“We think our work opens numerous opportunities for diagnosing, monitoring, and possibly treating MS,” said Ahmed Abdelhak, MD, assistant professor of neurology at UCSF and first and co-lead author of the paper.
“It could be a gamechanger for how we understand and manage this disease.”
The team identified about 50 proteins that herald future disease and have submitted a patent application for a diagnostic blood test using the top 21.
Among the immune signals, IL-3 stood out as critical during the early phase when the central nervous system is already being damaged but before symptoms appear.
“We now know that MS starts way earlier than the clinical onset, creating the real possibility that we could someday prevent MS — or at least use our understanding to protect people from further injury,” said Ari Green, MD, chief of the division of neuroimmunology and glial biology in the UCSF department of neurology and senior author.
